In the mixing bowl of a stand mixer, place the softened Butter, and mix with the whisk attachment, until the butter is light and fluffy.
Add the Vanilla, and mix until blended.
Combine the powdered sugar, and blend until smooth and creamy.
Mix in the flour, a little at a time, until it's all been added, and the shortbread is smooth.
In the microwave, melt the 1/4 cup of chocolate chips (1/3 cup if you like more chocolate), and add to the mixing bowl.
Blend well, until all the melted chocolate is blended.
Remove from the mixing bowl from the stand, and scrape down the sides of the bowl, and fold the shortbread with a large spoon, to completely blend.
Place the shortbread in 9 X 13 dish, and press evenly into the dish.
Add Sprinkles, or Nonpareils to the top of the shortbread, if desired.
Score the the shortbread with a sharp knife.
Bake at 300 degrees for about 45 minutes, or until the edges are light golden brown. Let the Shortbread cool until slightly warm.
Cut into bars, and move to a rack to finish cooling.
When cooled, sprinkle with mini chocolate chips, serve, and Enjoy!